The removal of toxic heavy metal ions from wastewaters is of great importance from an environmental viewpoint. Different agricultural residues were used for the removal heavy metals from aqueous solutions. In this study, the removal of Chromium and Nickel ions by Opuntia, a natural polyelectrolyte was investigated. The working concentration of metals used in this study was 10 mg/L. The different Opuntia polyelectrolyte concentrations used in this study was 5%, 10% and 20% (v/v). The equilibrium time needed for maximum metal removal was 18 h. The removal of both the ions was found to be Opuntia polyelectrolyte concentration and agitation speed dependent. 10%(v/v) Opuntia ficus indica polyelectrolyte and 150 rpm at 300 C are optimum conditions for removal of Cr and Ni ions from aqueous solution. Metal ion concentrations were determined by Spectrophotometer. The maximum removal of Cr and Ni by Opuntia polyelectrolyte after 18 h of equilibrium was 68% and 88.4% resp.
